Texas Instruments LM3424 Evaluation Board LM3424BKBSTEVAL/NOPB LM3424BKBSTEVAL/NOPB 데이터 시트
제품 코드
LM3424BKBSTEVAL/NOPB
I
L
ED
(
A
)
V
SW
(V)
60
40
20
0
1.0
0.5
0.0
I
LED
2
P
s/DIV
V
SW
I
L
ED
(
A
)
V
D
IM
(V)
10
5
0
1.0
0.0
-1.0
I
LED
V
DIM
4 ms/DIV
Typical Waveforms
9
Typical Waveforms
T
A
= +25°C, V
IN
= 24V and V
O
= 21V.
Figure 4. Standard Operation
Figure 5. 200Hz 50% PWM Dimming
TP1 Switch Node Voltage (V
SW
)
TP5 Dim Voltage (V
DIM
)
LED Current (I
LED
)
LED Current (I
LED
)
10
Alternate Designs
Alternate designs with the LM3429 evaluation board are possible with very few changes to the existing
hardware. The evaluation board FETs and diodes are already rated higher than necessary for design
flexibility. The input UVLO, output OVP, input and output capacitance can remain the same for the designs
shown below. These alternate designs can be evaluated by changing only R9, R10, and L1.
hardware. The evaluation board FETs and diodes are already rated higher than necessary for design
flexibility. The input UVLO, output OVP, input and output capacitance can remain the same for the designs
shown below. These alternate designs can be evaluated by changing only R9, R10, and L1.
gives the main specifications for four different designs and the corresponding values for R9, R10,
and L1. PWM dimming can be evaluated with any of these designs.
Table 2. Alternate Design Specifications
Specification /
Design 1
Design 2
Design 3
Design 4
Component
V
IN
10V - 45V
15V - 50V
20V - 55V
25V - 60V
V
O
14V
21V
28V
35V
f
SW
600kHz
700kHz
500kHz
700kHz
I
LED
2A
500mA
2.5A
1.25A
R9
0.05
Ω
0.2
Ω
0.04
Ω
0.08
Ω
R10
12.1 k
Ω
10.2 k
Ω
14.3 k
Ω
10.2 k
Ω
L1
22µH
68µH
15µH
33µH
14
AN-1967 LM3424 Buck-Boost Evaluation Board
SNVA397A – August 2009 – Revised May 2013
Copyright © 2009–2013, Texas Instruments Incorporated